And there are so many great bromance/frenemies (brenemies?) out there, ranging from pretty-much-BFFs to what-subtext-I'm-going-to-kill-you: Sherlock Holmes & Professor Moriarty. Jean Valjean & Inspector Javert. Professor X & Magneto. Batman & Joker. Peter Pan & Captain Hook. Johnny Weir & Evan Lysacek. Black Spy & White Spy. In the ladies' corner, I can really only think of Elphaba and Glinda off the top of my head, though I'd love to see more.
Don't worry, Moriarty. Fangirls will draw you sexxxy, unlike buzzkill Sidney Paget here..
There's something very reassuring about these long-lasting fictional relationships. They need each other. Batman can only use his advanced weaponry to harass citizens about parking tickets for so long before he looks like a jackass. Heroes can be timelessly earnest (and a bit boring), while villains can bring on the subversiveness. There's that opposites attract, two-sides-of-the-same-coin allure. Plus, simply by hanging out together (if "eternal war" equals "hanging out") for so long, there's a sort of camaraderie. After this many damn years, Ash might as well be a groomsman in James and Jessie's wedding if they decide to make it legal. Even if we can't imagine all insurance company executives or Syrian riot police suddenly turning good, we can imagine a truce between a few fictional people we've come to love, and that gives us the warm fuzzies.
Speaking of friendship, the film adaptation of Shakespeare's obsessed-enemies-turned-allies play Coriolanus is coming out in January (and you can read the LOL version here). The trailer makes it look like Vladimir Putin/Fidel Castro slash fanfiction starring Voldemort as Coriolanus and the "this is Spartaaaaa!!!" guy as Aufidius. Will it be good? It seems hopeful so far (and the movie's modern twist is certainly timely, with all the unrest going on across nations), but really, I will watch just about any Shakespeare adaptation anyway.